It happens quite often that a link (shared by e.g. email) pointing to a specific build, is no longer valid. QB in such cases displays message
"Entity Not Found. This normally happens when the entity you are accessing is deleted."

and "Back to Dashboard" button.

As we keep only a short history of builds, it happens very often and it is quite useless behaviour, because user doesn't even know where what was the configuration, the build was referring to.

Instead user should be given a chance to go to configuration overview page, so that s/he could see the status of recent builds for the given configuration (even though the specific build s/he tried to access no longer exists)